I recently met a middle school classmate of mine on the train.

He is an old acquaintance.

This ancient proverb, 'know the other side and yourself, and you will not be in danger in a hundred battles', teaches us the importance of understanding ourselves and others.

The shrine is a traditional Japanese building.

I hope our love will be eternal.

He is our class representative.

The steepest descent method is one way to solve optimization problems.

He is an expert in geophysics.

It took several hours to restore power after the blackout.

My laboratory is on the third floor of the university.